Phonograph tone arm and resonator



June 28,1927.- 1,533,624

vy. T CARNES PHONQGRAPH TQNE ARM AND RESONATOR Filed Dec. 19, 1923ran-ED STATES A Fatented June 28, 1927.

WILLIAM nonn vns, or KAnsAs CITY, MIssoUBI, Assreivonmo' onnnnsARTIFICIAL .ULIMB COMEANY,- or KANSAS CITY, ivrrssounr.

' rz'ronoennrn TONE AR Ann nnsorm'ron.

Application filed December 19, 1923. Serial No. 681,512.

My invention relates to. phonographs and particularly to. the tone armand amplifier thereof.

The object of this invention is to provide a tonearm which is swivelledon the upper end of the amplifier and will have no joints and restrictedportions between said swivel and the sound box. Also to form said tonearm on the lines of a parabola, gradually increasing in diameter fromthe free end there of to said swivel. Also to form the small end of theamplifier onthe lines of a parabola, thus eliminating the right angleelbow curves in said tone arm and amplifier. Also to provide ahinge-swivel joint between the tone arm and amplifier.

These and other features of invention will appear hereinafter and areillustrated in the accompanyingdrawings, in which": i Figure 1 is a sideelevation of my improved tone arm and amplifier.

Figure 2 is a: vertical section of my improved"hinge-swivel joint on-theline 22.

Figure 3 is a transverse section of the same on the line 33 in Fig. 1.

Figure 4 is a side elevation of the swivel ring of my invention.

Figure 5 is a plan View of the same.

Figure 6 is a rear View of the lower end of the bar G.

In these drawings, A indicates my improved tone arm, A indicates asound-box, and B indicates my improved amplifier; B is the curved neckof the amplifier B which joins the tone arm A.

I have eliminated'the usual sharp curve of a right angle elbow, and inlieu thereof my improved tone arm A is formed with the gradual curve ofa parabola from the free end a to the swivel end a, the diameter thereof gradually increasing from the end a to the end a of the tone arm,thus eliminating, as far as possible, interior pockets wherein there islittle or no longitudinal progress of tone waves within the tone arm A.

Within the free end a of the tone arm A is inserted the neck a of thesound-box A, which is secured therein by means of a set screw a Thissound-box, shown in the accompanying drawings, is the subject of aseparate application and forms no part of this invention. I

The resonator B is provided with an up turned neck B, which like thetone arm A is formed with parabolic curves, thus reducing the sharpcurves of aright-angle elbow, so that the natural expansion of soundwaves is not interfermredwith.

On the upper end of the neck B, I place a spider-ring, C, which 'issecured firmly. in place by means of bolts C which pass through ears 6,on'opposite sides of the neck B and screw into ears 0 on opposite sidesof the spider-ring C. r From the hub of the spider-ring, an upright postD projects upwardly, and upon this post D anotherspider ring E isjournalled, the hub E of the ring E is tubular and extends above theupper endof the post D. I

Upon the upper end of the post D, I place aball, e, and within the upperend of the hub tube E is placcd an adjusting screw F which carries thering E free from the spider-ringC. In the upper edge of the'ri'ng E arefound slots 0 e" at opposite sides or said ring whiclrrece-ive studs f friveted in diametrically opposite sides of the wall of the tone arm,which permits a vertical swing of the tone arm with relation to the ringE, while the ring E will freely turn on the post D. I

Riveted or otherwise secured to the tone arm A is a bar G which extendsdownwardly to a point opposite the rear of the amplifier B. The lowerend of the bar G is provided with a slit- 9, and a clip G is pressedover the lower end of said bar G being retained thereon by the frictionof said clip on the bar, enhanced by the elasticity of thesplit end ofsaid bar.

Secured to the frame H of the machine is a bracket H which projectsforwardly to the line of the axis of the swivel post D, and secured tothe clip G on the bar G is a cable H which is also secured in thebracket H and which serves to suspend the the receiving end thereof, anupright post supported upon said ring, a swivel ring journalled on saidpost, means to give Vertical adjustment to said ring with relation tosaid post, said ring having vertical slots in its' upper edge atdiametrically opposite points along the upper edge of its periphery, atone arm adapted to receive said ring, and trunnion studs secured in thewall of said arm and adapted to enter said slots.

2. In an apparatus of the class described, an amplifier, a'spider ringsecured on the receiving end thereof, an upright swivel post supportedon said ring, a swivel ring having a tubular hub and having verticalnotches in the upper edge thereof and having said tubular hub journalledon said upright post, an adjusting screw in the upper end of saidtubular hub adapted to support said swivel ring free from said spiderring, a tone arm adapted to receive said swivel ring, trunnion postssecured in the wall of said tone arm and entering said vertical slots,and means to limit the downward swing of said tone arm on said trunnionposts.

8. In an apparatus of the class described, an amplifier, a tubularswivel on the upper end thereof, and a'tapered, parabolic, tone armhaving the base thereof trunnioned on said swivel.

4;. In an apparatus of the class described, an amplifier, a tubularswivel on the upper end thereof, a curvedtone armtrunnioned on saidswivel, and means to support the free end of said tone arm.

5. In an apparatus of the class de'seribed, a tubular swivel ring havingoppositely disposed trunnion receiving slots in the upper edge thereof,a curved tone arm, trunnion posts on saidtone arm adapted to rest insaid slots, a downwardly extending arm secured to the rear of the saidtone arm, a case to enclose the said apparatus, and means to anchor thelower end of said arm to said case of said tone arm.

6. In an apparatus of the class described, an amplifier, a spider ringsecured on the receiving end thereof, a swivel post extending upwardlyfrom said ring, a swivel ring having notches extending downwardly indiametrically opposite points of the upper edge thereof, a tubular hubconnected to said ring and journalled on said post, a screw in the upperend of said tubular hub adapted to support said swivel ring out ofcontact with said spider ring, a tone arm adapted to receive said swivelring, trunnion studs on the inner surface of said tone arm adapted to belowered into said notches in the upper edge of said swivel ring, and anarm secured on. said tone arm and extending downwardly to anchor thelower end of said tone arm.

In testimony whereof I aflix my signature.

IVILLIAM T. CARNES.

